* [PATCH v2] NFSd: fix locking in nfsd_forget_delegations()
@ 2012-05-25 14:38 Stanislav Kinsbursky
2012-07-12 15:43 ` J. Bruce Fields
0 siblings, 1 reply; 3+ messages in thread
From: Stanislav Kinsbursky @ 2012-05-25 14:38 UTC (permalink / raw)
To: bfields; +Cc: linux-nfs, linux-kernel, devel
v2: dl_recall_lru list is used for delegations collect because it's modified
both in unhash_delegation() and nfsd_break_one_deleg().
This patch adds recall_lock hold to nfsd_forget_delegations() to protect
nfsd_process_n_delegations() call.
Also, looks like it would be better to collect delegations to some local
on-stack list, and then unhash collected list. This split allows to
simplify locking, because delegation traversing is protected by recall_lock,
when delegation unhash is protected by client_mutex.
Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
---
fs/nfsd/nfs4state.c | 21 +++++++++++++++++----
1 files changed, 17 insertions(+), 4 deletions(-)
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 21266c7..3d6848b 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -4694,7 +4694,7 @@ void nfsd_forget_openowners(u64 num)
printk(KERN_INFO "NFSD: Forgot %d open owners", count);
}
-int nfsd_process_n_delegations(u64 num, void (*deleg_func)(struct nfs4_delegation *))
+int nfsd_process_n_delegations(u64 num, struct list_head *list)
{
int i, count = 0;
struct nfs4_file *fp, *fnext;
@@ -4703,7 +4703,7 @@ int nfsd_process_n_delegations(u64 num, void (*deleg_func)(struct nfs4_delegatio
for (i = 0; i < FILE_HASH_SIZE; i++) {
list_for_each_entry_safe(fp, fnext, &file_hashtbl[i], fi_hash) {
list_for_each_entry_safe(dp, dnext, &fp->fi_delegations, dl_perfile) {
- deleg_func(dp);
+ list_move(&dp->dl_recall_lru, list);
if (++count == num)
return count;
}
@@ -4716,9 +4716,16 @@ int nfsd_process_n_delegations(u64 num, void (*deleg_func)(struct nfs4_delegatio
void nfsd_forget_delegations(u64 num)
{
unsigned int count;
+ LIST_HEAD(victims);
+ struct nfs4_delegation *dp, *dnext;
+
+ spin_lock(&recall_lock);
+ count = nfsd_process_n_delegations(num, &victims);
+ spin_unlock(&recall_lock);
nfs4_lock_state();
- count = nfsd_process_n_delegations(num, unhash_delegation);
+ list_for_each_entry_safe(dp, dnext, &victims, dl_recall_lru)
+ unhash_delegation(dp);
nfs4_unlock_state();
printk(KERN_INFO "NFSD: Forgot %d delegations", count);
@@ -4727,10 +4734,16 @@ void nfsd_forget_delegations(u64 num)
void nfsd_recall_delegations(u64 num)
{
unsigned int count;
+ LIST_HEAD(victims);
+ struct nfs4_delegation *dp, *dnext;
nfs4_lock_state();
spin_lock(&recall_lock);
- count = nfsd_process_n_delegations(num, nfsd_break_one_deleg);
+ count = nfsd_process_n_delegations(num, &victims);
+ list_for_each_entry_safe(dp, dnext, &victims, dl_recall_lru) {
+ list_del(&dp->dl_recall_lru);
+ nfsd_break_one_deleg(dp);
+ }
spin_unlock(&recall_lock);
nfs4_unlock_state();
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH v2] NFSd: fix locking in nfsd_forget_delegations()
2012-05-25 14:38 [PATCH v2] NFSd: fix locking in nfsd_forget_delegations() Stanislav Kinsbursky
@ 2012-07-12 15:43 ` J. Bruce Fields
2012-07-12 16:02 ` Bryan Schumaker
0 siblings, 1 reply; 3+ messages in thread
From: J. Bruce Fields @ 2012-07-12 15:43 UTC (permalink / raw)
To: Stanislav Kinsbursky; +Cc: linux-nfs, linux-kernel, devel, bjschuma
On Fri, May 25, 2012 at 06:38:50PM +0400, Stanislav Kinsbursky wrote:
> v2: dl_recall_lru list is used for delegations collect because it's modified
> both in unhash_delegation() and nfsd_break_one_deleg().
>
> This patch adds recall_lock hold to nfsd_forget_delegations() to protect
> nfsd_process_n_delegations() call.
> Also, looks like it would be better to collect delegations to some local
> on-stack list, and then unhash collected list. This split allows to
> simplify locking, because delegation traversing is protected by recall_lock,
> when delegation unhash is protected by client_mutex.
Thanks, applying for 3.6 (assuming Bryan doesn't have any objection).
--b.
>
> Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
> ---
> fs/nfsd/nfs4state.c | 21 +++++++++++++++++----
> 1 files changed, 17 insertions(+), 4 deletions(-)
>
> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> index 21266c7..3d6848b 100644
> --- a/fs/nfsd/nfs4state.c
> +++ b/fs/nfsd/nfs4state.c
> @@ -4694,7 +4694,7 @@ void nfsd_forget_openowners(u64 num)
> printk(KERN_INFO "NFSD: Forgot %d open owners", count);
> }
>
> -int nfsd_process_n_delegations(u64 num, void (*deleg_func)(struct nfs4_delegation *))
> +int nfsd_process_n_delegations(u64 num, struct list_head *list)
> {
> int i, count = 0;
> struct nfs4_file *fp, *fnext;
> @@ -4703,7 +4703,7 @@ int nfsd_process_n_delegations(u64 num, void (*deleg_func)(struct nfs4_delegatio
> for (i = 0; i < FILE_HASH_SIZE; i++) {
> list_for_each_entry_safe(fp, fnext, &file_hashtbl[i], fi_hash) {
> list_for_each_entry_safe(dp, dnext, &fp->fi_delegations, dl_perfile) {
> - deleg_func(dp);
> + list_move(&dp->dl_recall_lru, list);
> if (++count == num)
> return count;
> }
> @@ -4716,9 +4716,16 @@ int nfsd_process_n_delegations(u64 num, void (*deleg_func)(struct nfs4_delegatio
> void nfsd_forget_delegations(u64 num)
> {
> unsigned int count;
> + LIST_HEAD(victims);
> + struct nfs4_delegation *dp, *dnext;
> +
> + spin_lock(&recall_lock);
> + count = nfsd_process_n_delegations(num, &victims);
> + spin_unlock(&recall_lock);
>
> nfs4_lock_state();
> - count = nfsd_process_n_delegations(num, unhash_delegation);
> + list_for_each_entry_safe(dp, dnext, &victims, dl_recall_lru)
> + unhash_delegation(dp);
> nfs4_unlock_state();
>
> printk(KERN_INFO "NFSD: Forgot %d delegations", count);
> @@ -4727,10 +4734,16 @@ void nfsd_forget_delegations(u64 num)
> void nfsd_recall_delegations(u64 num)
> {
> unsigned int count;
> + LIST_HEAD(victims);
> + struct nfs4_delegation *dp, *dnext;
>
> nfs4_lock_state();
> spin_lock(&recall_lock);
> - count = nfsd_process_n_delegations(num, nfsd_break_one_deleg);
> + count = nfsd_process_n_delegations(num, &victims);
> + list_for_each_entry_safe(dp, dnext, &victims, dl_recall_lru) {
> + list_del(&dp->dl_recall_lru);
> + nfsd_break_one_deleg(dp);
> + }
> spin_unlock(&recall_lock);
> nfs4_unlock_state();
>
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH v2] NFSd: fix locking in nfsd_forget_delegations()
2012-07-12 15:43 ` J. Bruce Fields
@ 2012-07-12 16:02 ` Bryan Schumaker
0 siblings, 0 replies; 3+ messages in thread
From: Bryan Schumaker @ 2012-07-12 16:02 UTC (permalink / raw)
To: J. Bruce Fields; +Cc: Stanislav Kinsbursky, linux-nfs, linux-kernel, devel
On 07/12/2012 11:43 AM, J. Bruce Fields wrote:
> On Fri, May 25, 2012 at 06:38:50PM +0400, Stanislav Kinsbursky wrote:
>> v2: dl_recall_lru list is used for delegations collect because it's modified
>> both in unhash_delegation() and nfsd_break_one_deleg().
>>
>> This patch adds recall_lock hold to nfsd_forget_delegations() to protect
>> nfsd_process_n_delegations() call.
>> Also, looks like it would be better to collect delegations to some local
>> on-stack list, and then unhash collected list. This split allows to
>> simplify locking, because delegation traversing is protected by recall_lock,
>> when delegation unhash is protected by client_mutex.
>
> Thanks, applying for 3.6 (assuming Bryan doesn't have any objection).
Nope, I don't have any objections.
- Bryan
>
> --b.
>
>>
>> Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
>> ---
>> fs/nfsd/nfs4state.c | 21 +++++++++++++++++----
>> 1 files changed, 17 insertions(+), 4 deletions(-)
>>
>> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
>> index 21266c7..3d6848b 100644
>> --- a/fs/nfsd/nfs4state.c
>> +++ b/fs/nfsd/nfs4state.c
>> @@ -4694,7 +4694,7 @@ void nfsd_forget_openowners(u64 num)
>> printk(KERN_INFO "NFSD: Forgot %d open owners", count);
>> }
>>
>> -int nfsd_process_n_delegations(u64 num, void (*deleg_func)(struct nfs4_delegation *))
>> +int nfsd_process_n_delegations(u64 num, struct list_head *list)
>> {
>> int i, count = 0;
>> struct nfs4_file *fp, *fnext;
>> @@ -4703,7 +4703,7 @@ int nfsd_process_n_delegations(u64 num, void (*deleg_func)(struct nfs4_delegatio
>> for (i = 0; i < FILE_HASH_SIZE; i++) {
>> list_for_each_entry_safe(fp, fnext, &file_hashtbl[i], fi_hash) {
>> list_for_each_entry_safe(dp, dnext, &fp->fi_delegations, dl_perfile) {
>> - deleg_func(dp);
>> + list_move(&dp->dl_recall_lru, list);
>> if (++count == num)
>> return count;
>> }
>> @@ -4716,9 +4716,16 @@ int nfsd_process_n_delegations(u64 num, void (*deleg_func)(struct nfs4_delegatio
>> void nfsd_forget_delegations(u64 num)
>> {
>> unsigned int count;
>> + LIST_HEAD(victims);
>> + struct nfs4_delegation *dp, *dnext;
>> +
>> + spin_lock(&recall_lock);
>> + count = nfsd_process_n_delegations(num, &victims);
>> + spin_unlock(&recall_lock);
>>
>> nfs4_lock_state();
>> - count = nfsd_process_n_delegations(num, unhash_delegation);
>> + list_for_each_entry_safe(dp, dnext, &victims, dl_recall_lru)
>> + unhash_delegation(dp);
>> nfs4_unlock_state();
>>
>> printk(KERN_INFO "NFSD: Forgot %d delegations", count);
>> @@ -4727,10 +4734,16 @@ void nfsd_forget_delegations(u64 num)
>> void nfsd_recall_delegations(u64 num)
>> {
>> unsigned int count;
>> + LIST_HEAD(victims);
>> + struct nfs4_delegation *dp, *dnext;
>>
>> nfs4_lock_state();
>> spin_lock(&recall_lock);
>> - count = nfsd_process_n_delegations(num, nfsd_break_one_deleg);
>> + count = nfsd_process_n_delegations(num, &victims);
>> + list_for_each_entry_safe(dp, dnext, &victims, dl_recall_lru) {
>> + list_del(&dp->dl_recall_lru);
>> + nfsd_break_one_deleg(dp);
>> + }
>> spin_unlock(&recall_lock);
>> nfs4_unlock_state();
>>
>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at http://vger.kernel.org/majordomo-info.html
^ permalink raw reply [flat|nested] 3+ messages in thread
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2012-05-25 14:38 [PATCH v2] NFSd: fix locking in nfsd_forget_delegations() Stanislav Kinsbursky
2012-07-12 15:43 ` J. Bruce Fields
2012-07-12 16:02 ` Bryan Schumaker
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